Discharge electrode assembly

ABSTRACT

DISCHARGE ELECTRODE ASSEMBLIES ELECTRICAL PRECIPITATORS HAVING EXTENDED SURFACE COLLECTING ELECTRODES COMPRISE ELONGATE METALLIC RIBBONS DISPOSED WITH THE EDGES OF THE RIBBONS HAVING SUBSTANTIALLY PARALLEL PATHS IN PLANES PARALLEL TO AND SPACED FROM THE ASSOCIATED COLLECTING ELECTRODE FACES AND SUPPORT MEMBERS MAINTAINING THE RIBBONS RIGIDLY IN SUCH POSITION. IN PREFERRED ARRANGEMENTS THE METALLIC RIBBONS ARE BENT INTO AT LEAST PARTIALLY CURVILINEAR SHAPE.

March 16, 1971 F. w. SCHMITZ 3,570,219

" DISCHARGE ELECTRODE ASSEMBLY Filed Jan. 8, 1968 4 Sheets-sheet 1 llllllLll/I/Ill IIIII/IIIII IIII C DC DC DC DC DC F HE DC DC nrnnnn U3UUUUUUUU INVENTOR BY v ATTORNEY I) FREDERICK W. SCHMITZ 7 March 16, 1971 DISCHARGE ELECTRODE ASSEMBLY Filed Jan. 8,- 1968 III/IIII/ll/I F. w-. SCHMITZ 3,570,219

4 Sheets-Sheet 2 INVENTOR FREDERICK W. SCHMITZ ATTORNEY) March 16, 1 971 F, w, s z 3,570,219

DI SCHARGE ELECTRODE AS 5 EMHLY Filed Jan. 8, 1968 I Y 4 Sheets-Sheet 4 4 E IIIIIIIIIIIIIIIIIIIIII IICIII ll I I l/ I III f5 18 l5 I7 2 a q i l4 1 l4 s a e a E a E R E? INVENT OR ATTOR NEY 1 United States Patent Office 3,570,219 Patented Mar. 16, 1971 3,570,219 DISCHARGE ELECTRODE ASSEMBLY Frederick W. Schmitz, Plainfield, N.J., assignor to Research-'Cottrell, Inc., Bridgewater Township, Somerset County, NJ.

Filed Jan. 8, 1968, Ser. No. 696,247 Int. Cl. B03c 3/04 U.S. Cl. 55148 4 Claims ABSTRACT OF THE DISCLOSURE Discharge electrode assemblies electrical precipitators having extended surface collecting electrodes comprise elongate metallic ribbons disposed with the edges of the ribbons having substantially parallel paths in planes parallel to and spaced from the associated collecting electrode faces and support members maintaining the ribbons rigidly in such position. In preferred arrangements the metallic ribbons are bent into at least partially curvilinear shape.

The invention relates to discharge electrode assemblies suitable for use in electrical precipitators having extended surface collecting electrodes.

As is well known in the art, discharge electrodes for electrical precipitators include members having elements of relatively small radius of curvature, such as points or edges, to facilitate the formation of ionizing corona discharge under the influence of a strong electric field. Such members have commonly been formed of metallic wires or ribbons, typically rigidly supported at their upper ends and having weights or other tensioning means at their lower ends. However, under the combined stresses of strong electric fields and high velocity gas flow it has been found difiicult to maintain such discharge elements in the desired uniform spacing to obtain the maximum corona discharge while avoiding hot spots and arcing in the precipitation zone, which not only reduce the precipitation efficiency of the installation but require frequent repair or replacement of the discharge electrode structures.

These and other difliculties are avoided by the discharge electrode assemblies of the invention which comprise elongate metallic ribbons disposed with the edges of the ribbons tracing substantially parallel paths in planes parallel to and spaced from the associated collecting electrode faces and support members maintaining the ribbons rigidly in such position. Increased rigidity of the structures may be provided by bending the ribbons into at least partially curvilinear shape such as symmetrical loops.

The principles of the invention will be more fully described with reference to the accompanying drawings showing illustrative embodiments of the invention.

In the drawings:

FIG. 1 is a vertical section through an electrical precipitator having a discharge electrode assembly of the invention;

FIG. 2 is a fragmentary transverse section of the precipitator on line 2-2 of FIG. 1;

FIG. 3 is an enlarged pictorial illustration of one of the elements of the discharge electrode assembly of FIGS. 1 and 2;

FIG. 4 is a vertical section through an electrical precipitator having another form of the discharge electrode assembly of the invention;

FIG. 5 is a fragmentary transverse section of the precipitator on line 55 of FIG. 4; and

FIG. 6 is an enlarged pictorial illustration of one of the elements of the discharge electrode assembly of FIGS. 4 and 5.

In the drawings, 10 is the housing of a precipitator chamber having a gas inlet 11 on one side and a gas outlet 12 on the other. The housing is provided with the usual hopper bottom 13 for receiving and discharging precipitated materials from the chamber. Plate-type collecting electrodes 14 are supported longitudinally of the housing between the gas inlet and the gas outlet in spaced parallel relationship. The collecting electrodes are suspended from top support bars 15 which are supported on brackets 16 secured to inner walls of the housing adjacent its upper end.

Discharge electrode assemblies generally designated 17 are arranged in parallel spaced relationship intermediate the collecting plate electrodes 14 and in the embodiments illustrated are suspended by members 18 from insulator supports 19 mounted in conventional manner in insulator housings 20.

In the embodiment of FIGS. 1-3, the discharge electrode assemblies consist of metallic ribbons 21, typically of /2 inch wide No. 14 gauge steel strip formed into a series of symmetrical loops, for example, of 1% inch radius. The looped ribbons 21 are rigidly maintained in shape and position by a pair of parallel lateral steel strip members 22 welded at their upper and lower ends to metal bars 23 which are bolted or riveted to rectangular metal frames 24. The frames 24 are positioned intermediate the collecting plate electrodes and connected to suspension members 18 by horizontal bar 25.

In the embodiment of FIGS. 4-6, the discharge electrode assemblies consist of metallic ribbons 26, typically of /8 inch wide No. 16 gauge strip steel formed into continuous loops on 3% inch radii at the upper and lower ends. The looped ribbons 26 are rigidly maintained in shape and position by paired steel strip members 27 welded to the edges of the ribbons and to straps 28 which are bolted or riveted to the lower ends of hanger bars 29 connected by horizontal bars 30 to member 18.

I claim:

1. An electrical precipitator having extended surface collecting electrodes, a complementary discharge electrode assembly comprising elongate metallic ribbons disposed with the edges of the ribbons tracing substantially parallel paths, in planes parallel to and spaced from the associated collecting electrode faces and support members maintaining said ribbons rigidly in said position, said metallic ribbons each being bent away from their longitudinal axes into at least partially curvilinear shape.

2. An electrical precipitator as defined in claim 1 {wherein the metallic ribbons are bent into symmetrical oops.

3. An electrical precipitator as defined in claim 1 wherein the support members include parallel bars extendijng in supporting engagement with the edges of the ribons.

4. An electrical precipitator as defined in claim 2 wherein the support members include parallel bars extending in supporting engagement with the edges of the ribbons.

References Cited UNITED STATES PATENTS DENNIS E. TALBERT, JR., Primary Examiner U.S. Cl. X.R. 55151, 154 

